Our objective is to gain a better understanding of neural encoding in the auditory system as it pertains to communication by sound. Quantitative electrophysiological techniques form the core of our approach. These are complemented by behavioral studies of animal auditory performance. Immediate goals are 1) to gain a quantitative understanding of stimulus representation in the auditory periphery, with emphasis on the encoding of speech-like sounds; 2) to describe the encoding of vocalizations in the auditory systems of birds. Computer techniques and communication theory-oriented models are employed.